* Add ExecuteWorkflow activity and enable multitenancy
Introduced the ExecuteWorkflow activity to create and execute workflow instances, and updated runtime settings to use ProtoActor for distributed caching transport. Enabled multitenancy for the Elsa Server Web application.
* Namespace renames (#6135)
* Create ExecuteWorkflows tests and workflows
Add unit tests for executing workflows, including MainWorkflow and SubroutineWorkflow. Also, rename ExecutedWorkflowResult to ExecuteWorkflowResult in the runtime module for consistency.
* Add output definitions to WorkflowBuilder
Refactored the `WithInput` method for clarity and added multiple `WithOutput` methods to support different ways of defining workflow outputs. These changes enhance the flexibility and readability of the workflow configuration process by providing a consistent API for input and output definitions.
* Refactor namespaces in component tests
Updated namespaces from Helpers to specific contexts like Fixtures, Abstractions, Consumers, Decorators, etc., to improve code organization and readability. This change affects multiple files across different test scenarios and modules.
* Disable RabbitMQ and multitenancy, rename test class
Commented out RabbitMQ usage in WorkflowServer.cs to focus on other transports. Changed multitenancy flag to false in Program.cs. Renamed DispatchWorkflowsTests to ExecuteWorkflowsTests for clarity.